Neutrophil-to-lymphocyte ratio is a predictive marker for anti-MDA5 positive dermatomyositis

BACKGROUND: NLR is a systemic inflammatory marker that have been associated with overall survival in patients with some rapidly progressive disease. There are few data about the diagnostic and predictive value of NLR in autoimmune diseases, and it has not been described in anti-MDA5 positive DM. We try to correlate neutrophil-to-lymphocyte ratio (NLR) with fatality from dermatomyositis in anti-MDA5 positive patients. METHOD: A retrospective study in which 195 patients were enrolled was conducted. Clinical and laboratory information was collated and ratios of neutrophil to lymphocyte counts (NLR) calculated. The primary end point was all-cause death. RESULT: Of the 195 patients studied, all had interstitial lung disease, including 140 survivors and 55 non-survivors. An optimal NLR cut-off value of 4.86 for mortality prediction was identified. The NLR of non-survivors was significantly higher than that of survivors (p < 0.001). Plasma levels of lactate dehydrogenase (LDH) and C-reactive protein were significantly increased when NLR was greater than 4.86. Results of multivariate analysis established that NLR > 4.86 was an independent predictor of mortality (HR: 2.52; 95%CI: 1.33–4.78; p = 0.005). Abstinence from smoking (HR: 2.66; 95%CI: 1.33–4.78; p = 0.003), emergence of rapidly progressive interstitial lung disease (RPILD; HR: 4.38; 95%CI: 2.37–8.08; p < 0.001), low plasma LDH (HR: 3.82; 95%CI: 2.06–7.11; p < 0.001) and presentation with dyspnea (HR: 2.17; 95%CI: 1.22–3.86; p = 0.009) were all protective factors predictive of survival. CONCLUSION: NLR is a cost-effective and widely accessible biomarker with utility for risk stratification in patients with anti-MDA5 + dermatomyositis. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12890-022-02106-8.